GrapheneOS also has had this for a while. Mine is set to 18 hours.
this post was submitted on 15 Apr 2025
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I'm not a phone person. What benefit does this provide?
After a reboot all the data is encrypted and needs a pin/~~fingerprint~~ to unlock. So if it's stolen (or feds get it) a planned reboot resets it to a highly secure state that is much more difficult to hack into than when it's just locked from timeout. Edit: removed fingerprint, corrected below.
After a reboot all the data is encrypted and needs a pin/fingerprint to unlock.
Just to clarify, it needs a PIN/password to unlock after reboot. Biometrics like fingerprint aren't available until the device has been decrypted.
I was under the impression that if a phone restarts, then you cannot use biometrics. You have to use a pin/password/etc.
...that's exactly what I said...
Thanks for the clarification, I forgot that (somehow)
Oh, this is actually a useful feature, then.
Yeah, seems like its a move to follow apple after custom ROMS offering it as a security feature (Im on GrapheneOS and had it set for a while)
It makes it harder for law enforcement or others to access the phone without knowing the pin
And from my reading, helps secure against a situation where an police officer (AKA attacker in the US apparently..) coerces you to unlock the phone (or perhaps even just takes it off you in a locked, but active state), and stores it in a faraday bag with a charger. They do that to keep it 'alive' so their experts can break in - a dead-mans reboot can help circumvent even that (as it will just reboot and restore itself to an encrypted rest state, which is much harder to attack)
This podcast goes into the reasons that rebooting a locked phone can improve security.
[The 404 Media Podcast] How Apple is Locking Out Cops #the404MediaPodcast https://podcastaddict.com/the-404-media-podcast/episode/185990070 via @PodcastAddict
My take is, it's harder to unlock/hack a phone when it is in the locked state after booting up. This state is somehow different than the booted locked state.
Why, is above my understanding.
Basically, the tools that LE uses to unlock devices uses exploits that require the device to be in what's called an AFU (after first unlock) state. The data on the device is encrypted prior to that first unlock after you boot. If the device is in a BFU state (before first unlock) Cellebrite/Greykey (by far the primary tools used in this space) basically hit a wall.
Elsewhere in the thread they explain because decryption takes time, they don't cycle it every time you lock your phone by default. Not sure if there's more to it.
The time needed for key derivation aka key stretching may be a factor, but also in the BFU state I think apps don't run and you don't get notifications, since most of the files are still locked
Thank you for elaborating.
If you set it up with a password it makes it harder for people who shouldn't have access to it to read your stuff
the custom ROM I use (CalyxOS) already has it, and you can customise how long the device has to be locked for the reboot to occur, anywhere from 1 to 72 hours.
Same with GrapheneOS.
Mine is set for 12 hours. I never sleep that long and if it does reboot I don't care.
Thanks for this. Didn't even know it was an option.
I was gonna say I thought this had been the case forever. I don't use this feature but I recall seeing it on pretty much every custom ROM I've used over the last few years.
Mine already reboots every night. It's a setting I can change on my OnePlus.
I enabled it long ago. A reboot will also kill anything that is running in your memory like a page mining crypto or a virus that has not yet gotten to your file system yet. Or at least I'd like to think so....
Anyways, the reboot also insured that if my phone is ever taken from me, after 24 hours max they will have to both enter my PIN and my phone security code. I wish them good luck. There's not much interesting stuff on my phone, but that does not mean I want everyone to have free access too it.
NGL I’m shocked they weren’t doing this already, I seem to recall it being mentioned some android devices did this already when iOS added it last year(?)
At least some of the more security oriented ones?
I seem to recall it being mentioned some android devices did this already when iOS added it last year(?)
calyx os (it has better timing options still), graphene os, and it seems from another comment that oneplus too
Can this be done with Tasker?
Yes. Directly if you have root, or with a workaround where you bring up the power menu and then use either virtual keyboard commands or the AutoInput plugin to tap the reboot button.
I think so but it would take root or some kinda of workaround I think.
I reinstalled tasker again yesterday but then uninstalled it when it wouldn't work without giving it perms to draw over other apps.
I use automate instead.
Don’t some system updates require a reboot as well? Would be nice if this applied updates as part of this cycling.